Leviticus 16:29-31

And this shall be a statute for ever unto you: that in the seventh month, on the tenth day of the month, ye shall afflict your souls, and do no work at all, whether it be one of your own country, or a stranger that sojourneth among you: for on that day shall the priest make an atonement for you, to cleanse you, that ye may be clean from all your sins before the LORD. It shall be a sabbath of rest unto you, and ye shall afflict your souls, by a statute for ever.